Conventionally, it has been reported to use a reaction product of an organic compound having two hydroxyl groups and phosphine (for example, 2,2′-(phenylphosphide)bis(6-tert-butyl-4-methylphenoxide)(tetrahydrofuran)titanium dichloride) for production of olefin polymers (for example Japanese Patent Application Laid-Open (JP-A) No. 10-218922).